µC Implements Pushbutton Light Dimmers:  06/18/98 EDN-Design Ideas / (added 08/05) A project required building a synchronous-demodulator circuit to track a line drawn on paper.  beauty of  synchronous-modulator/demodulator approach is its inherent noise rejection.  method rejects nearly all out-of-band noise, wher from internal drift or external illumination. This rejection is a boon in optical tracking, where  return signal is inevitably buried in 120-Hz ambient light, amplifier offsets, and temperature drifts.  circuit in Figure 1 is inexpensive, and it operates from 5V dc.  circuit scans eight LED/sensor pairs every 22 msec and stores  result in eight sample/hold (S/H) capacitors for interrogation by a µP-driven ADC.  purpose of  circuit is to determine which sensor is above  line.

0 to 10 Volt Analog Control Protocol:  (design circuit added 8/02)

1.5 Volt LED Flashers:  four circuits with description (added 4/02)

10 Channel LED Sequencer:  based on4017 (added 4/02)

10 Stage Light Sequencer:  flashes10 low voltage bulbs, operates at10-25-Volt voltage, in PDF format, text in Finnish (added 4/02)

12 Stage Neon Sequencer (NE 2/NE 51):  uses small power 70-Volt neon bulbs (added 4/02)

12 Volt DC Fluorescent Lamp Driver:  This fluorescent lamp driver uses a normal 120 to 6V step-down transformer in reverse to step12V to about350-Volt to drive a lamp without  need to warm  filaments. (added 4/02)

12 Volt Lamp Dimmer:  dimming d1-by controlling  duty cycle of a astable555 Timer oscillator (added 4/02)

12 Volt Lamp Fader (Automatic ):  (electronic schematic / circuit added 11/05)

12 Volt Strobe Circuit:  this circuit uses12V DC instead od mains AC. This is very good idea if you don't want to mess with direct mains voltage connected circuit or you want to run  stroboscope from batteries. (added 4/02)

120 VAC Lamp Chaser using Solid State Relays:  (electronic circuit added 7/03)

120 VAC Lamp Dimmer (Full Wave SCR):  (electronic circuit added 10/05)

120 Volt AC Lamp Chaser using Solid State Relays:  This circuit is similar to  LED clock using12 neon indicator lamps instead of LEDs. It operates from2 high capacity ni-cad cells (2.5 volts) which keep it going for a couple weeks. High voltage (70 volts) for  neon lamps is obtained from a small switching power supply using a 74HC14 Schmitt trigger Squarewave oscillator, high voltage switching transistor, and10 mH high Q inductor. Most any small PNP transistors can be used that have a C/E voltage rating of 80 or more. (added 4/02)

120 Volt AC Lamp Dimmer (Full Wave SCR):  (circuit added 7/02)

120VAC Lamp Chaser using Solid State Relays:  (electronic circuit added 4/05)

12V DC Fluorescent Lamp Driver:  (electronic circuit added 4/05)

12V florescent light inverter:  (electronic circuit added 2/07)

12VDC Fluorescent Lamp Driver:  (circuit / schematic design added 11/06)

16 Stage Bidirectional LED Sequencer:  (circuit added 7/02)